We wish to study the recognition of specific nucleotide sequences by regulatory proteins, and how these interactions control gene functioning in the E. coli bacteriophage lambda. We plan to determine the nucleotide sequences of certain operators and promoters in this phage, and to determine the amino-acid sequence of the lambda repressor. We shall study binding of repressor to its reiterated binding sites utilizing specific DNA fragments produced by DNA restriction enzymes, as well as purified operators. Similar studies are planned with RNA polymerase and its binding and transcription-initiation sites on lambda DNA. Utilizing isolated controlling elements of DNA, we shall study how sequence recognition promotes or represses transcription and we shall study the effects of mutation on these processes. Experiments are also planned that should elucidate the molecular mechanism of UV-induced repressor inactivation.